Despite previous research efforts, the relationship between cancer and stressful life events remains unresolved. The goal of this research is to elucidate whether an association between the incidence of cancer and demise from cancer in general, or of specific neoplasms, are related to parental bereavement by using a design that overcomes limitations encountered in previous studies. We propose to test the following hypotheses: l) Bereavement is a delayed risk factor for cancer onset. More specifically, bereavement may increase the incidence for cancer associated with risk-engaging behavior, e.g., lung cancer, and those associated in part with neuroendocrine dysfunction, e.g., breast cancer. For bereaved men, as they are prone to risk-engaging behavior, the increased morbidity/mortality is hypothesized to be particularly higher among neoplasms related to such behaviors. The increased risk for women is hypothesized to be greater among the neuroendocrine-related neoplasms, possibly resulting from their increased vulnerability for depression when bereaved. 2) Bereavement accelerates the progression or demise of cancer patients, measured by its increased aggressiveness and reduction of survival. This is expected to occur for cancers that occur both before and after the loss. To test these hypotheses, we will conduct an epidemiological investigation in Israel with the specific aim of linking an already identified bereaved population cohort, built with the help of NIMH grant 1-R01-MH-37923-Ol, and the Israel Cancer Registry. The bereaved sample consists of approximately 6,300 parents who lost an adult son in the 1973 Yom Kippur War or due to accidents that occurred between 1971 and 1975, thus allowing over seventeen years of follow-up. Unlike previous research, this study based on parental loss eliminates the problems associated with conjugal bereavement: 1) The bereaved can not change his/her condition, such as by remarriage, resulting in a chronic stress; and 2) it avoids the contaminating effects of assortative mating or joint exposure to the same hazardous environment.